Final answer:
The missing side of a triangle with a perimeter of 720 cm and two known sides of 230 cm and 210 cm is found to be 280 cm by using an algebraic equation and solving for the unknown side.
Step-by-step explanation:
To find the length of the missing side of a triangle with a perimeter of 720 cm, when two of the sides are 230 cm and 210 cm, we can set up the following algebraic equation:
Let the length of the missing side be represented by x. The perimeter P of a triangle is the sum of the lengths of all its sides, so we have:
P = side1 + side2 + side3
720 cm = 230 cm + 210 cm + x
To solve for x, we subtract the sum of the two known side lengths from the total perimeter:
720 cm - (230 cm + 210 cm) = x
720 cm - 440 cm = x
280 cm = x
Therefore, the length of the missing side is 280 cm.